define an anonymous closure in swift

An anonymous closure, also known as a lambda function, can be defined in Swift using the following syntax:

main.swift
{ (parameters) -> return type in
    // code to be executed
}
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4 lines

Here's an example of an anonymous closure that takes two integers as parameters and returns their sum:

main.swift
let sum = { (a: Int, b: Int) -> Int in
    return a + b
}

print(sum(5, 10)) // Output: 15
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In this example, the sum constant is assigned an anonymous closure that takes two integers (a and b) as parameters and returns their sum as an integer. The closure is then called with the arguments 5 and 10, which outputs the value 15 to the console.

Anonymous closures are useful for creating small, one-time use functions that don't require a separate function definition. They can be passed as arguments to other functions, or assigned to constants and variables just like any other value in Swift.